MIC27600_11 Datasheet, PDF (1/28 Pages) Micrel Semiconductor – 36V, 7A Hyper Speed Control™ Synchronous DC-DC Buck Regulator

MIC27600
36V, 7A Hyper Speed Control™
Synchronous DC-DC Buck Regulator
SuperSwitcher II™
General Description
Features
The Micrel MIC27600 is a constant-frequency, synchronous
buck regulator featuring a unique digitally-modified adaptive
on-time control architecture. The MIC27600 operates over an
input supply range of 4.5V to 36V and provides a regulated
output of up to 7A of output current. The output voltage is
adjustable down to 0.8V with a guaranteed accuracy of ±1%,
and the device operates at a switching frequency of 300kHz.
Micrel’s Hyper Speed Control™ architecture allows for ultra-
fast transient response while reducing the output capacitance
and also makes (High V_IN)/(Low V_OUT) operation possible.
This digitally modified adaptive t_ON ripple control architecture
combines the advantages of fixed-frequency operation and
fast transient response in a single device.
The MIC27600 offers a full suite of protection features to
ensure protection of the IC during fault conditions. These
include undervoltage lockout to ensure proper operation
under power-sag conditions, internal soft-start to reduce
inrush current, foldback current limit, “hiccup” mode short-
circuit protection and thermal shutdown.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
• Hyper Speed Control™ architecture enables
- High Delta V operation (V_IN = 36V and V_OUT = 0.8V)
- Small output capacitance
• 4.5V to 36V voltage input
• Adjustable output from 0.8V to 5.5V (V_HSD ≤ 28V)
• Adjustable output from 0.8V to 3.6V (V_HSD ≤ 36V)
• ±1% FB accuracy
• Any Capacitor™ Stable - Zero-ESR to high-ESR
• 7A output current capability, up to 95% efficiency
• 300kHz switching frequency
• Internal compensation, 6ms Internal soft-start
• Foldback current-limit and “hiccup” mode short-circuit
protection
• Thermal shutdown
• Supports safe startup into a pre-biased load
• –40°C to +125°C junction temperature range
• 28-pin 5mm × 6mm MLF^® package
Applications
• Distributed power systems
• Communications/networking infrastructure
• Set-top box, gateways and routers
• Printers, scanners, graphic cards and video cards
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Typical Application
Efficiency (VIN = 28V)
vs. Output Current
95
5.0V
90
3.3V
2.5V
85
1.8V
80
1.5V
1.2V
1.0V
75
0.9V
0.8V
70
65
60
0123456789
OUTPUT CURRENT (A)
Hyper Speed Control, SuperSwitcher II and Any Capacitor are trademarks of Micrel, Inc.
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
July 2011
M9999-070811